Jeff Shollenberger of Mohrsville says he works hard to follow good safety practices at his stand in the Shillington Farmers Market, where he knows many of his customers personally. "God forbid I'd make a customer sick," he says. "It's twice as bad."

Higher levels of salmonella and campylobacter, which can cause diarrhea, were found in whole chickens purchased from farmers markets than in chickens bought from grocery stores, according to a small-scale study by Penn State University.

The discrepancy may stem from U.S. Department of Agriculture's poultry exemption status, which does not require anyone who processes fewer than 20,000 chickens a year to have daily USDA facility inspections, said Cathy Cutter, lead researcher for the study.

"We got 100 birds from a number of different places across Pennsylvania," she said. "One hundred was reasonable for what we were trying to do: Get a small snapshot of what's out there."

The study, which was funded by the university, led Cutter and her team to consider distributing information to farmers and vendors in farmers markets about food safety, Cutter said.

"Some facilities didn't have the food safety programs or antimicrobial interventions," she said. "Maybe we should develop extension outreach for the farmers and vendors so they could garner information from their processors."

Joshua Scheinberg of Cherry Hill, N.J., who conducted the research for his master's degree in food science, said the study was meant to help vendors.

"The focus is not to alienate farmers," Scheinberg said. "It is to develop training to support farmers markets. Our focus was to try to improve food safety."

Farmers market chickens were not the only birds to test positive for bacteria. For comparison, Scheinberg and Cutter tested 50 organic chickens and 50 conventionally processed chickens from grocery stores.

"We were evaluating a raw product," Scheinberg said. "Potentially, even if the whole bird is fully contaminated, as long as you cook that product properly you'll destroy those pathogens."

That means ensuring the whole chicken is cooked until it reaches an internal temperature of 165 degrees, he said.

Other tips include avoiding cross-contamination in your kitchen by thoroughly cleaning any surface the raw chicken has touched and refrigerating the chicken as soon as possible after purchase.

At the Shillington Farmers Market, Jeff Shollenberger of Shollenberger Organic Produce takes cleanliness seriously. Since he considers many of his customers friends, Shollenberger said he has even more of an incentive to keep his stand clean.